/*
 *  Copyright 1999-2019 Seata.io Group.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package io.seata.server.storage.file;

import java.nio.ByteBuffer;

import io.seata.common.exception.ShouldNeverHappenException;
import io.seata.server.session.BranchSession;
import io.seata.server.session.GlobalSession;
import io.seata.server.store.SessionStorable;
import io.seata.server.store.TransactionStoreManager.LogOperation;

/**
 * The type Transaction write store.
 *
 * @author slievrly
 */
public class TransactionWriteStore implements SessionStorable {

	private SessionStorable sessionRequest;

	private LogOperation operate;

	/**
	 * Instantiates a new Transaction write store.
	 * @param sessionRequest the session request
	 * @param operate the operate
	 */
	public TransactionWriteStore(SessionStorable sessionRequest, LogOperation operate) {
		this.sessionRequest = sessionRequest;
		this.operate = operate;
	}

	/**
	 * Instantiates a new Transaction write store.
	 */
	public TransactionWriteStore() {
	}

	/**
	 * Gets session request.
	 * @return the session request
	 */
	public SessionStorable getSessionRequest() {
		return sessionRequest;
	}

	/**
	 * Sets session request.
	 * @param sessionRequest the session request
	 */
	public void setSessionRequest(SessionStorable sessionRequest) {
		this.sessionRequest = sessionRequest;
	}

	/**
	 * Gets operate.
	 * @return the operate
	 */
	public LogOperation getOperate() {
		return operate;
	}

	/**
	 * Sets operate.
	 * @param operate the operate
	 */
	public void setOperate(LogOperation operate) {
		this.operate = operate;
	}

	@Override
	public byte[] encode() {
		byte[] bySessionRequest = this.sessionRequest.encode();
		byte byOpCode = this.getOperate().getCode();
		int len = bySessionRequest.length + 1;
		byte[] byResult = new byte[len];
		ByteBuffer byteBuffer = ByteBuffer.wrap(byResult);
		byteBuffer.put(bySessionRequest);
		byteBuffer.put(byOpCode);
		return byResult;
	}

	@Override
	public void decode(byte[] src) {
		ByteBuffer byteBuffer = ByteBuffer.wrap(src);
		byte[] bySessionRequest = new byte[src.length - 1];
		byteBuffer.get(bySessionRequest);
		byte byOpCode = byteBuffer.get();
		this.operate = LogOperation.getLogOperationByCode(byOpCode);
		SessionStorable tmpSessionStorable = getSessionInstanceByOperation(this.operate);
		tmpSessionStorable.decode(bySessionRequest);
		this.sessionRequest = tmpSessionStorable;
	}

	private SessionStorable getSessionInstanceByOperation(LogOperation logOperation) {
		SessionStorable sessionStorable = null;
		switch (logOperation) {
			case GLOBAL_ADD:
			case GLOBAL_UPDATE:
			case GLOBAL_REMOVE:
				sessionStorable = new GlobalSession();
				break;
			case BRANCH_ADD:
			case BRANCH_UPDATE:
			case BRANCH_REMOVE:
				sessionStorable = new BranchSession();
				break;
			default:
				throw new ShouldNeverHappenException("incorrect logOperation");
		}
		return sessionStorable;
	}

}
